When Breathing Isn’t Easy
Marsha was vacationing in Spain when she received a call from the University of California at Davis informing her that her filly Nevita was in intensive care at the veterinary hospital with severe difficulty breathing. She was diagnosed with asthma.
By Patti Schofler N
evita had a difficult birth. A longtime breeder, Marsha Busekist had seen a few of these and she was glad she was there to assist in bring- ing the Lusitano filly into the world. That
night in April 2017, Marsha was relieved the newborn was all right—a little lethargic and coughing a little, but there were seemingly no major issues as the symptoms improved. But the northern California filly developed pneu- monia, likely from inhaling amniotic fluid during birth. A course of antibiotics did the trick and within five days she was breathing normal. All was well again until four months later, when on a day
in late August the sky over Nevita’s home turned orange. Acres upon acres in central and northern California were on fire in what would prove to be the worst year on record for California fires. Less than three hundred miles away from Nevita, 49,000 acres burned to the north, nearly 18,000 acres burned to the south, nearly 7,000 acres to the east and upwards of 7,500 acres to the northwest. The temperature in Nevita’s town was measuring well over 100 degrees, making breath- ing a challenge. Soon afterward, Marsha got the call from the vet hospital.
The California fires of 2017 were recorded as the worst the state ever experienced.
UNDERSTANDING BREATHING DISORDERS Equine asthma is a chronic disease of the airways. Inflamma- tion and mucus in the airways impede the air flow vital for health, performance and day-to-day activities. When gallop- ing, the horse breathes in oxygen only through the nose. It travels down the trachea, which joins the lung and divides into left and right main stem bronchi. The bronchi divide into
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smaller tubes called bronchiole and finally into small pocket- like structures called alveoli. The body needs oxygen (O2) to produce energy for exer- cise and other activities, and then needs to shed carbon diox- ide (CO2), which is the waste gas of energy production. The alveoli are the meeting place where the CO2-O2 exchange takes place. The heart pumps blood through the blood vessels in the lungs which, like the airways, branch and get smaller and smaller until very small “pulmonary capillaries” pass in intimate contact with the alveoli. “The CO2 jumps off the blood cells as pulmonary capillar-
ies pass around the alveoli. At the same time, the O2 inhaled into the lungs jumps from the alveoli onto the cells, oxygen- ating the blood, turning it red. The CO2 in the alveoli is forced out of the lungs when the horse exhales,” explains Dr. Jim Chiapetta, a veterinarian and CEO of FLAIR Equine Nasal Strips. When all is not well, as with all forms of asthma, including
inflammatory airway disease (IAD), recurrent airway obstruc- tion (RAO), and chronic obstructive pulmonary disease (COPD), the lower airways (the bronchi and bronchioles in the lungs) respond with an inflammatory reaction to the environment, allergen or agent. The body recognizes a virus or bacteria or allergen as foreign and defends itself by releas- ing inflammatory fluids and white blood cells. Mucus and white blood cell production cause the airways to spasm. The mucosal lining of the airways become inflamed and thicker, narrowing the diameter of the airways. The overall composi- tion of the airways changes. The passageway of the tubular airways is now formed by
inflamed, thickened walls and filled with mucus and pus. The bands of muscle that wrap around the airways and control their diameter spasm and contract to further squeeze down the size of the airway, reducing airflow into the alveoli and negatively impacting the oxygen-CO2 exchange that takes place there. Any disruption of the airflow along this route impacts
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